unusually exuberant foliage this spring. causes?

1) The exceedingly mild winter (no true freeze, not one, where I live in Atlanta)

2) the continuously moist conditions.

These might be causes of the extraordinary leafing out this spring.

I'm wondering if high CO2 might be another cause. Plants love that. (In the recent reporting about the milestone recorded in Hawaii, there was also a note that the parts per million will now decline seasonally as the leafing out in the Northern Hemisphere gets going.)

The warm winter, the early last frost-free date, and the moisture certainly seem to have a direct relationship to the "lush" character of all the components of my plantings and garden.

If the high CO2 contributed positively, however, next year's foliage may be negatively impacted due to the larger number/size of this year's foliage.

Having done a complete front and side yard landscaping early Fall last year, I'm pleased that EVERY flower and shrub (save one Forsythia) over-wintered safely and are all looking very healthy. In addition, the almost 3000 sq.ft. of new Zoyzia sod is exceptionally healthy, weed-free, and completely "greened-out" (we're ready to cut it for the second time this Spring already).